Two major UK cities have reported outbreaks of measles and there are fears it could spread to neighbouring locations. There have been cases in both Leeds and Liverpool, with the Mirror saying health experts reckon Greater Manchester could be next.
NHS Choices says: "This infectious viral illness is easily spread and can lead to complications. Ask your GP about the vaccine if you, or your children, haven't had two doses."
Measles is highly infectious but hasn't been very prevalent in the UK in recent years because of widespread vaccination efforts.
Symptoms can include similar feelings to a cold, like a runny nose, sore red eyes that might be sensitive to light, a high temperature and small, greyish-white spots on the inside of your cheek. People who begin to experience those symptoms are urged to contact their GP immediately, even if it turns out to be nothing - it's better to be safe than sorry.
Signs of the illness usually start to appear between 10 to 12 days after being infected and can last more than a week. It's an airborne illness and is usually spread when sufferers sneeze or cough into the open air.
More than 20 million people contract it every year, however that's usually concentrated in Africa and Asia, where vaccination rates aren't as high compared to the US. The death rate from measles has been dropping dramatically over the decades; with roughly 2.6 million people dying from the illness in 1980, 545,000 perished a decade later, and 73,000 in 2014.
Incredibly, North and South America became the first region to completely eliminate the illness last year.
In a statement, World Health Organisation Director Carissa F. Etienne said: "This is a historic day for our region and indeed the world. It is proof of the remarkable success that can be achieved when countries work together in solidarity towards a common goal.
"It is the result of a commitment made more than two decades ago, in 1994, when the countries of the Americas pledged to end measles circulation by the turn of the 21st century.
"This historic milestone would never have been possible without the strong political commitment of our Member States in ensuring that all children have access to life-saving vaccines."
The easiest way to prevent contracting it in the UK is to get the MMR vaccine, which covers you for measles, mumps and rubella. Thankfully doctors have chucked all that in one injection to avoid getting jabbed three separate times.